1. Field of the Invention
This invention relates to an electric steam iron and in particular, to a steam generating and extracting system for high rates of steam generation.
2. Background Information
Generally, most electric steam irons in use today employ a "flash" steam system wherein water contained in a water reservoir is dropped directly on a hot soleplate to generate steam. The generated steam is usually super-heated and its temperature is proportional to the soleplate temperature. It has been found that relatively high temperature super-heated steam is not as effective for ironing garments as steam at or near saturated conditions (100.degree. C.). It has also been determined that saturated steam with some moisture content can relax the fabric of the garment being ironed and result in a more satisfactorily ironed garment. It has also been determined that the use of relatively high steam rates can significantly improve the ironing characteristics of many common fabrics.
Typically, in irons using the "flash" steam system, the steam is directed through a tortuous path to separate any entrained water from the steam. The typical tortuous path is reasonably effective for moderate steam rates, e.g. 10 grams of steam per minute. The effectiveness of a typical tortuous path however does not generally permit steam to be generated at all ironing temperatures or at relatively high steam rates. Generally, electric steam irons start to water spot at about 130.degree.-135.degree. C. at a steam rate of only 10 grams per minute. This shortcoming with conventional irons is particularly important since it has been found that superior ironing results for moisture sensitive fabrics such as cotton and cotton blends can be obtained by utilizing wet steam at lower than conventional temperatures, e.g. 110.degree.-150.degree. C. and at relatively high steam rates. These ironing conditions reduce the risk of scorching damage to the garment that can occur at the higher conventional ironing temperatures commonly used for cottons, e.g. 175.degree.-195.degree. C.
Additionally when using a higher steam rate such as 20 grams per minute at the higher temperatures conventionally used for cotton and cotton blends, e.g. 145.degree.-175.degree. C., water spotting can occur due to the limited effectiveness of typical tortuous paths and soleplate designs. These designs can typically only support high steam rates at the highest temperature settings of the iron e.g. 175.degree.-205.degree. C., without water spotting the garment.
There have been some attempts to overcome the foregoing problem by the use of very high steam chambers with tall vertical walls cast into the iron's soleplate. The very height of these walls under most circumstances prevents relatively large droplets of water from escaping the steam generating chamber. The foregoing, while being generally effective in reducing water spotting at high steam rates and low temperatures, adds significant expense to the cost of the iron, consumes much space, and adds a significant amount of weight which makes the iron less user friendly.
It is accordingly an object of this invention to generate relatively low temperature steam at relatively high steam rates without significantly increasing the height and/or weight of the iron.